A thermodynamic description of the Al–B–Er system

Abstract The Al–B–Er ternary system was optimized by means of the CALPHAD (CALculation of PHAse Diagram) technique. The solution phases, liquid and hcp, were described by the substitutional solution model. The compounds AlB 12 , AlB 2 , B 2 Er, B 4 Er, B 12 Er, B 66 Er, AlB 4 Er and AlB 14 Er were treated as stoichiometric compounds. In the present study, in order to describe the structural relationship between the solution phase fcc(A1) (disordered part) and the phase L1 2 ( cP 4-AuCu 3 -type, ordered part), the two phases were modeled as (Al,B,Er) 1 (Va) 1 and (Al,B,Er) 0.75 (Al,B,Er) 0.25 (Va) 1 , respectively. A self-consistent thermodynamic description of the Al–B–Er system was obtained.